1. Field of the Invention
The present invention relates to a terminal structure of high frequency signal transmitting part, for example, a terminal structure which is applicable to a terminal for transmitting high frequency signals of a high frequency relay.
2. Description of the Related Art
Conventionally, as a high frequency relay which constitutes one of high frequency signal transmitting parts, there has been considered, for example, a structure which arranges a contact mechanism between two shield plates which face each other in an opposed manner in the vertical direction with a given gap therebetween. By arranging the contact mechanism between two shield plates which face each other in an opposed manner in the vertical direction, it is possible to interrupt jumping of electric waves from the outside and to prevent irradiation of electric waves to the outside thus ensuring the excellent high frequency characteristics.
However, in such a high frequency relay, due to the presence of two shield plates, it is difficult to pull out terminals for transmitting high frequency signal from an upper or lower surface of a housing. Accordingly, the terminals for transmitting high frequency signal is projected in a sideward direction from a side face of the housing and is bent downwardly so as to enable an electrical connection with a printed circuit board. As a result, although the high frequency signal relay exhibits the excellent high frequency characteristics by itself, since portions of the terminals are exposed to an external space and hence, the terminals have suffered from a high frequency loss attributed to the connection structure of the terminals. For example, when a large number of high frequency relays 1 shown in FIG. 11 are mounted on a printed circuit board 3 in a concentrated manner, the portions of the exposed terminals 2 are liable to easily receive the influence of high frequency signals irradiated from other high frequency signal relays 1. Further, the high frequency signals irradiated from the exposed portions of the terminals 2 are reflected on housings of other high frequency relays 1 and jump into the portions of the terminals 2 and hence, there has been a drawback that the high frequency characteristics are degraded.
The present invention has been made in view of the above-mentioned drawbacks and it is an object of the present invention to provide a terminal structure of a high frequency signal transmitting part which can enhance the high frequency characteristics of terminals for transmitting high frequency signals which are projected in a sideward direction from side faces of a housing of the high frequency signal transmitting part and are bent thereafter.
The terminal structure of a high frequency signal transmitting part according to the present invention is directed to a terminal structure of a high frequency signal transmitting part in which a high frequency signal transmitting terminal is projected in the sideward direction from a side face of a casing and is bent, wherein an outer face of the projected high frequency signal transmitting terminal is covered with an extension portion of a shielding member in a non-contact state.
Due to such a constitution, according to the present invention, the outer face of the high frequency signal transmitting terminal can be electromagnetically shielded by the extension portion of the shielding member so that the high frequency characteristics can be enhanced.
Further, according to one embodiment of the present invention, the extension portion of the shielding member may have a width equal to or more than a width of the high frequency signal transmitting terminal.
Due to the above-mentioned embodiment, the electromagnetic shielding is performed by the extension portion of the shielding member having the wide width and hence, the high frequency characteristics are further enhanced.
According to another embodiment, a gap defined between the high frequency signal transmitting terminal which is projected from the casing in the sideward direction and the extension portion of the shielding member may be set uniform.
Due to this embodiment, the gap defined between the high frequency signal transmitting terminal and the extension portion of the shielding member can be made uniform so that the high frequency characteristics can be enhanced.
According to still another embodiment, an earth terminal may be directly extended from the extension portion of the shielding member.
Due to this embodiment, the shielding member may be mounted on a printed circuit board through the earth terminal thus providing an advantageous effect that the availability of the terminal structure of the high frequency signal transmitting part can be enhanced.